Problem: On the way to school, Karen became fixated on the puzzle game on her phone!

<image>

The game is played as follows. In each level, you have a grid with n rows and m columns. Each cell originally contains the number 0.

One move consists of choosing one row or column, and adding 1 to all of the cells in that row or column.

To win the level, after all the moves, the number in the cell at the i-th row and j-th column should be equal to gi, j.

Karen is stuck on one level, and wants to know a way to beat this level using the minimum number of moves. Please, help her with this task!

Input

The first line of input contains two integers, n and m (1 ≤ n, m ≤ 100), the number of rows and the number of columns in the grid, respectively.

The next n lines each contain m integers. In particular, the j-th integer in the i-th of these rows contains gi, j (0 ≤ gi, j ≤ 500).

Output

If there is an error and it is actually not possible to beat the level, output a single integer -1.

Otherwise, on the first line, output a single integer k, the minimum number of moves necessary to beat the level.

The next k lines should each contain one of the following, describing the moves in the order they must be done:

  * row x, (1 ≤ x ≤ n) describing a move of the form "choose the x-th row". 
  * col x, (1 ≤ x ≤ m) describing a move of the form "choose the x-th column". 



If there are multiple optimal solutions, output any one of them.

Examples

Input

3 5
2 2 2 3 2
0 0 0 1 0
1 1 1 2 1


Output

4
row 1
row 1
col 4
row 3


Input

3 3
0 0 0
0 1 0
0 0 0


Output

-1


Input

3 3
1 1 1
1 1 1
1 1 1


Output

3
row 1
row 2
row 3

Note

In the first test case, Karen has a grid with 3 rows and 5 columns. She can perform the following 4 moves to beat the level:

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In the second test case, Karen has a grid with 3 rows and 3 columns. It is clear that it is impossible to beat the level; performing any move will create three 1s on the grid, but it is required to only have one 1 in the center.

In the third test case, Karen has a grid with 3 rows and 3 columns. She can perform the following 3 moves to beat the level:

<image>

Note that this is not the only solution; another solution, among others, is col 1, col 2, col 3.

Solution (in CPP):

Solution:
#include <bits/stdc++.h>
using namespace std;
int n, m, g[110][110], gg[110][110], r[110], c[110], ar[510][110], ac[510][110];
bool pd(int ii) {
  for (int i = 0; i < n; ++i)
    for (int j = 0; j < m; ++j)
      if (gg[i][j] != ar[ii][i] + ac[ii][j] || ar[ii][i] < 0 || ac[ii][j] < 0)
        return false;
  return true;
}
int main() {
  cin >> n >> m;
  for (int i = 0; i < n; ++i) {
    r[i] = 2147483646;
    for (int j = 0; j < m; ++j) {
      cin >> g[i][j];
      gg[i][j] = g[i][j];
      r[i] = min(r[i], g[i][j]);
    }
  }
  for (int i = 0; i < m; ++i) {
    c[i] = 2147483646;
    for (int j = 0; j < n; ++j) c[i] = min(c[i], g[j][i]);
  }
  int w = -1, minn = 2147483646;
  for (int ii = 0; ii <= r[0]; ++ii) {
    ar[ii][0] = ii;
    for (int j = 0; j < m; ++j) ac[ii][j] = g[0][j] - ar[ii][0];
    for (int i = 0; i < n; ++i)
      for (int j = 0; j < m; ++j) g[i][j] -= ac[ii][j];
    for (int i = 1; i < n; ++i) ar[ii][i] = g[i][0];
    if (pd(ii)) {
      int ans(0);
      for (int i = 0; i < n; ++i) ans += ar[ii][i];
      for (int i = 0; i < m; ++i) ans += ac[ii][i];
      if (minn > ans) {
        minn = ans;
        w = ii;
      }
    }
    for (int i = 0; i < n; ++i)
      for (int j = 0; j < m; ++j) g[i][j] = gg[i][j];
  }
  if (w != -1) {
    cout << minn << endl;
    for (int i = 0; i < n; ++i)
      for (int j = 0; j < ar[w][i]; ++j) cout << "row " << i + 1 << endl;
    for (int i = 0; i < m; ++i)
      for (int j = 0; j < ac[w][i]; ++j) cout << "col " << i + 1 << endl;
  } else
    cout << "-1" << endl;
  return 0;
}